#include<iostream>
using namespace std;

class adc
{
public:
	friend class dac;
	int a;	
};
class dac
{
public:
	int b;
	void show(adc&tmp)
	{
		cout<<tmp.a;
	}	
};

int main()
{
	adc adc_;
	adc_.a=2;
	dac dac_;
	dac_.show(adc_);
	return 0; 	
}
